Interface control

ABSTRACT

A method and apparatus for the extrusion of multilayered composite products, is provided. In accordance with the inventive method, the relative orientation of a first shaped flow stream and a second shaped flow stream to one another is changed, and the reoriented shaped streams are melt-laminated to produce a layered composite formed independent of division of a layered precursor stream. Beneficially, layered flow streams that differ from one another may be used. Differences in volumetric or mass flow rates may also be used to advantage. The inventive apparatus includes a coextrusion structure and a partition member. The coextrusion structure may advantageously include one or more removably disposed, flow-shaping inserts, and the partition member may be a removably disposed, partition plate. The inventive apparatus beneficially further includes a removably disposed flow sequencer for changing the relative orientation of the flow streams.

FIELD OF THE INVENTION

This invention relates to the coextrusion of multilayered compositestructures.

BACKGROUND OF THE INVENTION

As exemplified by U.S. Pat. No. 5,122,905 to Wheatley et al and U.S.Pat. No. 6,982,025 to Bonk et al, it is known to produce interdigitatedstreams, for instance, of an repetitive ABAB layer configuration, inwhich A and B are rheologically diverse from one another. Certain ofthese composites are disclosed as providing advantageous opticalproperties. In the Bonk et al patent, other composites are disclosed asbenefitting gas barrier use, cushioning, and resistance against flexfatigue. These composites include microlayers, and it is disclosed thatthese composites can be made by coextrusion.

U.S. Pat. No. 4,426,344 to Dinter et al is directed to a coextrusionprocess that includes the formation of layered composite streams havingcontinuous, but nonplanar interfaces, by profiling the contact surfacesof merging streams. In accordance with the process, Dinter et al formthe layered composite streams in different planes, and thereafterreposition the streams from a stacked orientation to an edge-to-edgecoplanar relationship while reducing width, prior to joining the streamslaterally. Thereafter in accordance with the process, the resultingfluid mass is extruded from a downstream die as a multilayered product.FIG. 2 of Dinter et al illustrates multilayered product consisting oftwo joined halves, as indicated by the phantom line in the Figure.

U.S. Pat. No. 5,094,788 to Schrenk et al, U.S. Pat. No. 5,094,793 toSchrenk et al, and U.S. Pat. No. 5,269,995 disclose technology by whicha shaped layered stream of discrete and continuous layers of diversethermoplastic materials is used to generate a plurality of interfacialsurfaces in a molten polymeric mass. In this type of prior art, a shapedlayered stream flowing in a direction designated z of an x-y-zcoordinate system, and including a generally planar interface that liesin the x-z plane, is divided into a plurality of branch streams. Thedivision into branch streams is along the x-axis, and is generallyparallel to the z-axis. The x-axis defines a transverse dimension of theinterface. Thus, a plurality of branch streams is produced by dividingan interface of a shaped layered stream; and the term “branch streams”as used in this art, means layered streams derived by division of alayered precursor stream.

Thereafter, the branch streams are reoriented relative to the x-axis andthe y-axis, so that the branch streams are in a stacked orientation inthe y-direction. The reoriented branch streams are combined in anoverlapping relationship to generate interdigitated streams including aplurality of interfacial surfaces.

The '788, '793 and '995 type of prior art also discloses independentlyadjusting the flow rates of branch streams, and dimensionally changingstreams in the x-direction and y-direction. In addition, the '995 patentdiscloses the use of protective boundary layers to avoid layerinstability and breakup at interfaces in microlayer coextrusion, andthereby avoid adverse effect on desired optical and/or mechanicalproperties.

A drawback of the '788 and '793 type of prior art is that in the case oflayered streams with adjacent layers of diverse rheological properties,interface distortion and hence layer deformation or distortion, mayresult from, for instance, time dependent migration. A further drawbackof this type of prior art is layer interfacial instability; the use ofprotective boundary layers as in the '995 type of prior art, addsadditional layers that may not be desirable for, or necessarily benefit,the intended use.

In addition, in the '788, '793 and '995 type of prior art, the resultantcomposite structures are limited to interdigitated layered structures.Also, layer distortion can be expected to be relatively greater withrelatively more mechanical manipulation of shaped layered streams.

Accordingly, there is a need particularly when processing diversethermoplastic materials, to form composite structures with reducedinterface distortion, and thereby reduced layer deformation anddistortion. Furthermore, there is a need to eliminate, or minimize thedevelopment of, layer interfacial instability, and it is desirable toachieve such a result without reliance upon protective boundary layers.It is desirable not only to minimize mechanical manipulation of shapedlayered streams, but also to improve microlayer coextrusion.

Also needed are multilayered composite products including layers ofimproved performance, for instance, improved barrier layer performanceor reduced stress-cracking, and multilayered composite products of morevaried layer composition. The composite structure may be useful as abarrier, for example, as a gas, moisture or flavor barrier. Improvedbarrier performance will for instance, benefit pressurized bladders forfootwear, as well as be advantageous in packaging of varied types.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided an improvedmethod for producing a shaped layered composite having an interfacedefined by melt-lamination of flow streams. In accordance with theinventive method, the interface lies generally in an x-z plane of anx-y-z coordinate system, the x-axis defines a transverse dimension ofthe interface, and the y-axis extends generally perpendicularly throughthe interface.

In accordance with the inventive method, the relative orientation of afirst shaped flow stream and a spaced apart, second shaped flow streamto one another, is changed, and the reoriented flow streams arecombined. The first shaped flow stream may be a layered stream thatincludes at least one interface made by merging a first plurality offlow streams, and the second shaped flow stream may be a layered streamthat includes at least one interface made by merging a second pluralityof flow streams. By the term “plurality” is meant for purposes of thisfeature of the invention, two or more, including up to that needed formicrolayer coextrusion. In accordance with the inventive method whenforming a layered stream, a substantial difference in volumetric or massflow rates of at least two of the streams being merged, may be used, ifdesired, to control the relative volume or mass of the layers.

Alternatively, either or both flow streams may be monolayer streams. Inaccordance with the inventive method, whether the flow streams beingreoriented are layered streams or monolayer streams, the flow streamsare suitably shaped for melt-lamination.

In accordance with the method, with the first shaped flow stream and thesecond shaped flow stream each having a main flow direction generally ina direction designated z of the x-y-z coordinate system, the flowstreams are changed from a first relative orientation to a secondrelative orientation. In a preferred embodiment, the flow streams arereoriented from a generally side-by-side orientation along the x-axis toa generally stacked orientation in which the first shaped flow streamdefines a first plane and the second shaped flow stream defines a secondplane along the y-axis. In the generally side-by-side orientation, theflow streams may be in the same plane or in different planes. There may,of course, be additional flow streams.

Subsequently, the shaped layered composite is formed by melt-laminatingthe first shaped flow stream and the second shaped flow stream, therebyalso generating the earlier-mentioned interface. In accordance with theinventive method and distinct from '788 type of prior art, the layeredcomposite is formed independent of division of a layered precursorstream. Thus, the first shaped flow stream and second shaped-flowstream-can advantageously differ from one other not only in volume andlayer thickness but when they are layered streams, also in otherstructure including but not limited to layer composition is includinglayer sequencing. As indicated, additional streams may be melt-laminatedto produce additional interfaces of the layered composite. In accordancewith the inventive method, a substantial difference in volumetric ormass flow rates of the streams being melt-laminated may be used.

Thereafter, in accordance with the inventive method, this interface ofthe shaped layered composite is dimensionally increased along the x-axisto form a multilayered composite product of greater width than thicknessin which this interface is generally parallel to the width.Illustrative-products are multilayered sheet products. For purposes ofthis invention, the term “multilayered” includes product having at leasttwo layers, and the term “sheet” includes, and thus should not beinterpreted as excluding, product typically identified in the art asfilm.

Also provided by the present invention is an apparatus for producing amultilayered composite product. The apparatus includes in a preferredembodiment, a coextrusion structure partitioned into a first coextrusionsubstructure and a second coextrusion substructure, by a partitionmember. The first coextrusion substructure includes a first flow-shapingchannel in fluid communication with a first flow convergence channel,and the partition member advantageously forms a wall portion of thefirst flow-shaping channel. Beneficially, the second coextrusionsubstructure includes a second flow-shaping channel and a thirdflow-shaping channel in fluid communication with a second flowconvergence channel, and the partition member may also form a wallportion of the second flow-shaping channel. If desired, the partitionmember may have one or more stream-dividing walls.

In a second preferred embodiment, the inventive apparatus includes afirst flow-shaping structure, a first flow-shaping channel in fluidcommunication with a flow convergence channel, and a partition member,and the first flow-shaping structure is partitioned by the partitionmember so as to comprise a second flow-shaping channel in fluidcommunication with the flow convergence channel, and a thirdflow-shaping channel. Beneficially in this embodiment, a coextrusionstructure is formed by the first flow-shaping channel, the secondflow-shaping channel, and the flow convergence channel, and thepartition member may form a wall portion of the first flow-shapingchannel.

In any case, the inventive apparatus may beneficially further include aremovably disposed flow sequencer for changing relative flow streamorientation prior to melt-lamination of the streams. In accordance withthe invention, inlets of a flow sequencer useful in the inventiveapparatus, are disposed generally side-by-side.

The coextrusion structure may advantageously include one or moreremovable flow-shaping inserts, and the partition member may be aremovable partition plate. Apparatus according to the invention, mayfurther include an additional partition member or members.

Additional advantages and beneficial features of the present inventionare set forth in the drawing and detailed description, and in part willbecome apparent to those skilled in the art upon examination of thedrawing and detailed description or may be learned by practice of theinvention. In the drawing and detailed description, preferredembodiments of the invention are shown and described by way ofillustration of the best mode contemplated of carrying out thisinvention. As will be realized, this invention is capable of other anddifferent embodiments, and its several details are capable ofmodification in various respects, all without departing from theinvention. Accordingly, the drawing and the detailed description are tobe regarded as illustrative in nature, and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference is now made to the accompanying drawing, which forms a part ofthe specification of the present invention.

FIG. 1 depicts changing the relative orientation of shaped layeredstreams and melt-laminating the streams to produce a shaped layeredcomposite, and thereafter producing a multilayered composite product, inaccordance with the present invention;

FIG. 2 is a perspective view of a preferred apparatus in accordance withthe present invention, with most structure for fluid flow shown in solidline for clarity of view, the apparatus being useful in connection withthe method depicted in FIG. 1;

FIG. 3 is a detailed view of the flow sequencer of the apparatus of FIG.2, with flow cavities shown in solid line for clarity;

FIG. 4 is an exploded view showing components of the flow sequencer ofFIG. 3;

FIGS. 5, 6 and 7 pertain to a second preferred embodiment of the presentinvention;

FIG. 8 is a perspective view of another preferred embodiment;

FIGS. 9 and 10 pertain to yet another preferred embodiment; and

FIG. 11 is a perspective view of still another preferred embodiment.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with the present invention, interface distortion and hencelayer deformation and distortion are reduced. In addition, developmentof layer interfacial instability is minimized or may even be prevented,and this result may be accomplished without reliance upon protectiveboundary layers. Mechanical manipulation of shaped layered streams isreduced. Moreover, the present invention benefits microlayercoextrusion.

As a result of the invention, multilayered composite products includinglayers of improved performance are obtainable. In addition, multilayeredcomposite products with more varied layers, are obtainable.

Referring to FIGS. 1 and 2, in accordance with the present invention, afirst layered stream 12 including an interface 14 having a width w, isformed from precursor streams A,B. Likewise, a second layered stream 22including an interface 24 having a width w′, is formed from precursorstreams C,D. As mentioned, a plurality of additional streams up to thatneeded for microlayer coextrusion, may be used. Furthermore, if desired,additional layered streams may be formed.

With reference now in particular to FIG. 2, an apparatus 10 includescoextrusion substructures 26 a,26 b, which form precursor streams into ashape suitable for coextrusion and form geometrically defined, layeredstreams 12,22. A feed channel 15 a conveniently connects between anextruder (not shown) for precursor stream A, and coextrusionsubstructure 26 a. Stream A flows into a manifold 30 a andspreads-in-the manifold in a direction generally transverse to a maindirection of stream A flow indicated by an arrow located in apreconvergence channel 34 a. From the flow-shaping channel manifold,stream A enters preconvergence channel 34 a of the flow-shaping channel.

Similarly, a feed channel 16 a conveniently connects between an extruder(not shown) for precursor stream B, and a flow-shaping insert 2 a ofcoextrusion substructure 26 a. Stream B, advantageously Theologicallydiverse in properties from stream A, flows into a manifold 40 a andspreads in the manifold in a direction generally transverse to a maindirection of stream B flow indicated by an arrow located in apreconvergence channel 44 a. From the manifold, stream B enterspreconvergence channel 44 a of coextrusion substructure 26 a.

As stream A and stream B exit from preconvergence channels 34 a,44 a tomerge in a flow convergence channel 46 a of coextrusion substructure 26a, the shaped streams each advantageously have a width that respectivelycorresponds to width w of channel 34 a and width w of channel 44 a, andupon merging, form melt-laminate 12 (shown in FIG. 1), which includesinterface 14 (likewise having width w) between the stream layers.

With continued reference to FIG. 2 in particular, feed channels 15 b,16b conveniently connect between extruders (not shown) for precursorstreams C and D, and coextrusion substructure 26 b. Streams C and D,typically Theologically diverse in properties from one another,respectively enter a manifold 30 b, and a manifold 40 b of aflow-shaping insert 2 b. In the manifolds, streams C,D spread in adirection generally transverse to a main direction of stream flowindicated for each by an arrow located in respective preconvergencechannels 34 b,44 b. From manifolds 30 b,40 b, streams C,D enter therespective preconvergence channels 34 b,44 b. Thereafter, streams C,Dexit from preconvergence channels 34 b,44 b to merge in a flowconvergence channel 46 b of coextrusion substructure 26 b, the shapedstreams each advantageously having a width that respectively correspondsto width w′ of channel 34 b and width w′ of channel 44 b, and uponmerging, form melt-laminate 22 (shown in FIG. 1), which includesinterface 24 (likewise having width w′) between the stream layers.

As may be understood from FIG. 2, manifolds 30 a,40 a of coextrusionsubstructure 26 a beneficially provide the streams exiting frompreconvergence channels 34 a,44 a with width w, and manifolds 30 b,40 bof coextrusion substructure 26 b beneficially provide the streamsexiting from preconvergence channels 34 b,44 b with width w′. However,as a skilled artisan will appreciate, width w or w′ could, for instance,alternatively be provided downstream of a manifold by increasing ordecreasing stream width in the respective preconvergence channel. Also,although it is beneficial for width w and width w′ to substantiallycorrespond to one another when layered streams 12,22 are formed, askilled artisan will appreciate that width w may be greater or less thanwidth w′ when layered streams 12,22 are formed.

The relative volume of the layers in each of layered streams 12,22 canbe controlled by relative volumetric throughput. As described by U.S.Pat. No. 5,389,324 to Lewis, typical techniques for controlling relativevolumetric flow rate include the use of temperature differential toaffect relative stream viscosities, and the use of flow passagegeometry, for instance, the use of substantial differences in length,height and/or width of respective flow paths; and a multilayeredstructure with a layer thickness gradient can be thereby formed. Inaccordance with the present invention, a substantial difference inoutput of respective extruders can also be utilized.

Conveniently, a relatively greater extruder output is used for stream Bthan for stream A, as a result of which the flow volumes of streams A,Bare substantially different as these streams form layered stream 12,which is thus characterized by, as indicated by FIG. 1, relativelygreater volume of the B layer than the A layer. If desired, relativevolumetric or mass flow rate could be used to effect greater volume ormass of the A layer compared to the B layer in melt-laminate 12, or asindicated for layered stream 22, the layers may be substantially equalin mass.

As also indicated in FIG. 1, geometrically defined streams 12,22 eachhave a thickness t, which is generally perpendicular to respectiveinterfaces 14,24. Streams 12,22 can be wider than thicker (as shown),square, or thicker than wider. In any event, in accordance with theinvention, streams 12,22 are suitably shaped for subsequentmelt-lamination. By suitably shaped for melt-lamination or suitablyshaped for coextrusion, is meant for purposes of this invention, thatthe flow streams to be melt-laminated or coextruded include at least oneplanar surface. Similarly, by “flow-shaping” as used in this descriptionto describe features such as a flow-shaping channel or flow-shapinginsert, is meant that the channel or insert produces a flow streamhaving a least one planar surface.

From the foregoing it can therefore be understood that in accordancewith an advantageous embodiment of the present invention, a shapedlayered stream including a continuous, generally planar interface havingwidth w, is formed by merging shaped streams likewise having width w,and a shaped layered stream including a continuous, generally planarinterface having width w′, is formed by merging shaped streams likewisehaving width w′. Thus, unlike the Schrenk et al prior art, shapedlayered streams for producing a shaped layered composite bymelt-lamination are formed independently of one another. Accordingly, bythe method of the present invention, there is no layered precursorstream common to layered streams 12,22, with the result that layeredstreams 12,22 are formed free of division of a layered precursor streamand hence are not branch streams. Therefore, layered flow streammanipulation is reduced. Benefits include less interface distortion andless layer deformation and distortion.

Referring again to FIG. 2, coextrusion substructure 26 a and coextrusionsubstructure 26 b together constitute a coextrusion structure, which inaccordance with the present invention, is partitioned into substructures26 a,26 b by a partition member 28. In this regard, an elongated portion28 a of partition member 28 defines manifolds 30 a,30 b by partitioning,defines preconvergence channels 34 a,34 b by partitioning, and definesflow convergence channels 46 a,46 b by partitioning. Furthermore,elongated portion 28 a of the partition plate provides a side wall 32 aof manifold 30 a, preconvergence channel 34 a and flow convergencechannel 46 a, and a side wall (not shown) of manifold 30 b,preconvergence channel 34 b, and flow convergence channel 46 b.

Moreover, the partition member includes an arm 28 b, which extendsbetween-and is disposed adjacent to shaping inserts 2 a,2 b. In thisway, arm 28 b, which is illustrated as being oriented generallyperpendicular to elongated portion 28 a, separates manifolds 40 a,40 b,and separates preconvergence channels 44 a,44 b, of shaping inserts 2a,2 b, and provides a side wall 32 b of manifold 40 a and preconvergencechannel 44 a, and a side wall (not shown) of manifold 40 b andpreconvergence channel 44 b.

The partition member is beneficially a removable partition plate.Likewise, flow-shaping inserts 2 a,2 b are beneficially removable fromthe body of apparatus 10. However, removability is not a necessaryfeature of a useful partition member or useful flow-shaping structure.

Beneficially, the-partition member is generally centrally disposedwithin the coextrusion structure, with respect to the transverse flowdirection. As a result, the partitioning produces coextrusionsubstructures 26 a,26 b generally equal to one another in the transverseflow direction, and including for example, manifolds 30 a,30 b isgenerally equal to one another in the transverse flow direction, andchannels 46 a,46 b likewise generally equal to one another in thetransverse flow direction.

With continued reference to FIG. 2 and referring also to FIG. 3,side-by-side channels 46 a,46 b are in fluid communication with a flowsequencer 50, and more specifically, as shown, with inlets 52 a,52 b toflow-sequencing channels 54 a,54 b of flow sequencer 50. Flow-sequencingchannels 54 a,54 b change in relative orientation to one another from acoplanar, side-by-side orientation at inlets 52 a,52 b to a stackedorientation as they converge to form an interface generating channel 53.As described later, the flow sequencer, like partition plate 28 andinserts 2 a,2 b, may be beneficially removably inserted in a cavity inthe body of apparatus 10.

Referring also to FIG. 1 and to the x-y-z coordinate system depicted, inwhich x, y and z are oriented generally perpendicular to one another, atinlets 52 a,52 b of sequencer 50, generally rectangularly shaped,layered streams 12,22 are conveniently disposed side-by-side along thex-axis. Within the flow sequencer, shaped streams 12,22 each flowgenerally in the main flow or z-direction, with interfaces 14,24generally in alignment with the x-axis and hence generally perpendicularto the y-axis. In accordance with the invention, the shaped streams,while flowing generally in the z-direction, are oriented and sequencedwithin sequencer 50 by flow-sequencing channels 54 a,54 b from theside-by-side orientation along the x-axis to a stacked orientation inwhich, like branch streams of FIG. 1 of the '788 patent, shaped stream12 defines a first plane and shaped stream 22 defines a second planealong the y-axis. As noted, the main flow direction defines thez-direction; thus, the z-direction, as well as the x-axis and y-axis,changes with change in the main flow direction. Although reorienting ofis both of streams 12,22 along the x-axis and y-axis is shown, a skilledartisan will recognize that reorienting of only one stream along thex-axis and y-axis may be sufficient.

With continued reference to FIGS. 1 to 3, in interface generatingchannel 53 of sequencer 50, reoriented streams 12,22, suitably shapedfor melt-lamination, are combined along major surfaces thereof definedby an x-z plane of the x-y-z coordinate system, to generate acontinuous, generally planar interface boundary 64 in a shaped layeredcomposite 62 consisting of shaped layers stacked in the y-direction. Itcan thus be understood that because unlike the Shrenck et al prior art,there is no layered precursor stream common to layered streams 12,22,shaped layered composite 62 is formed independent of division of alayered precursor stream.

As indicated in FIG. 1, stream 22 conveniently contributes a relativelygreater proportion of the volume or mass of shaped layered composite 62,than stream 12 contributes. As before, the relative volume or mass canbe controlled by relative volumetric or mass throughput. Conveniently,relatively greater extruder output is used for streams C,D than forstreams A,B, as a result of which the flow volumes of layered streams12,22 are substantially different as shaped layered composite 62 isformed by melt-lamination in interface generating channel 53. Ifdesired, relative volumetric or mass flow rates could be used to effectrelatively greater volume or mass of shaped stream 12 than shaped stream22 in shaped layered composite 62, or the reverse, or the contributionto composite 62 could be substantially equal. Conveniently, shapedstreams 12,22 substantially correspond to one another in width, andedges of stream 12 are aligned with edges of stream 22, when forminginterface 64.

Thereafter, referring again to FIG. 2, shaped layered composite 62 ispassed from the flow sequencer is through a dimension-altering channel55 that leads to a connecting channel 56 that terminates in an exit slot57 of apparatus 10. More precisely, referring also to FIG. 3, interfacegenerating channel 53 leads to an exit slot 58 of the flow sequencer,and thereafter in channel 55, which includes opposing walls 59 disposedrelative to one another for conveniently increasing the stream width,shaped layered composite 62 is increased in width prior to exit fromapparatus 10. The relatively increased width of composite 62 will reducethe width ratio of composite 62 to a downstream die.

Thereafter in accordance with the invention, shaped layered composite 62is passed from apparatus 10 directly or indirectly into an appropriateconventional downstream extrusion die, from which a multilayered sheetproduct 69 illustrated in FIG. 1, exits. If desired, composite 62 couldbe converged with one or more like streams that have been similarlyformed, prior to entry into the downstream extrusion die. With continuedreference to FIG. 1, sheet 69 has a width W greater than a thickness T,the sheet width typically being increased by processing in the extrusiondie; and interface 64 generated in flow sequencer 50 is generallyparallel to the sheet width W. Relative to a useful extrusion die,attention is drawn to FIG. 1 of U.S. Pat. No. 4,426,344 to Dinter et al,which generally depicts a downstream extrusion die, and this aspect ofDinter et al is hereby incorporated by reference into this description.However, unlike the product shown in FIG. 2 of Dinter et al, in whichthe newly formed interface and the prior formed interfaces are generallyperpendicular to one another, interface 64 generated after streamreorientation, is generally parallel to prior formed interfaces 14,24.

Thus, in accordance with the invention, a multilayered composite productincluding layers of reduced deformation or distortion and hence ofimproved performance, is obtainable by the present invention. Inaddition, because the subject invention does not require use of branchstreams, composite products of more varied layer composition, areobtainable. For example, the four layers of sheet product 69 may bediverse in properties from one another and hence represented as A/B/C/D,whereas with the Schrenk et al prior art, an interdigitated structurewith a layer composition of A/B/A/B would result. Furthermore, asillustrated by the embodiment of apparatus 310, interface generationdoes not require at a minimum, doubling the total number of layers.Moreover, when the present invention is applied to microlayercoextrusion, improved results are obtainable.

Arrows located in flow convergence channel 46a and connecting channel 56indicate a main direction of fluid flow from formation of streams 12,22to exit of shaped layered composite 62 from apparatus 10. Side plates(not shown) enclose coextrusion structure 26 and the remaining otherwiseexposed-structure of apparatus 10, including flow sequencer 50 anddownstream channel 56.

Generally speaking, consistent with avoiding division of a layeredprecursor stream (division being taught by the Shrenck et al prior art),it is preferred that any dimensional or shape modification of a shapedlayered stream be minimized. However, a skilled artisan will recognizethat the dimensions of shaped layered streams may be modified asappropriate to meet specific process or product requirements. Thus,dimensional manipulation of one or both of shaped layered streams 12,22may be effected prior to forming interface 64. In addition, the shape ofshaped layered composite 62 can be modified to meet specific process orproduct requirements. Generally, change in thickness and/or width willbe carried out, as previously indicated, after exit of a shaped islayered stream from apparatus 10. Thus, depending upon requirements,manipulation of shaped layered streams by change in flow channelgeometry, may be minimized.

Referring to FIGS. 3 and 4, flow sequencer 50 beneficially is anassembly of a plurality of plates 76,77,78 with surface channels80,81,82,83, as shown and indicated in plate faces 85,86,87,88,respectively, which combine to form flow-sequencing channels 54 a,54 b,and inlets 52 a,52 b of channels 54 a,54 b. Thus, inlet 52 a and channel54 a are provided by surface channel 82, which includes an inlet channelportion 90 and a flow convergence-promoting channel portion 91, in face87 of plate 77, and by opposing surface channel 83 in opposing face 88of plate 78. Likewise, inlet 52 b and channel 54 b are provided bysurface channel 80 in face 85 of plate 76, and by opposing surfacechannel 81, which includes an inlet channel portion 92 and a flowconvergence-promoting channel (or exit channel) portion 93, in opposingface 86 of plate 77.

With continued reference to FIGS. 3 and 4, interface generating channel53 and exit slot 58 of the flow sequencer are formed in part by opposingside walls 94 (indicated in FIG. 4) of plate 77. Alignment pins andcorresponding bores (not shown) advantageously provide for alignment ofplates 76,77,78 and of the surface channels with one another.

Referring to FIG. 5, in accordance with the present invention, a firstfive-layered melt-laminate 112 including interfaces 114 having a widthw, is formed from precursor streams. Likewise, a second five-layeredmelt-laminate 122 including interfaces 124 having a width w″, is formedfrom precursor streams.

With reference to FIG. 6, an apparatus 110 is shown that differs fromapparatus 10 of FIG. 2 primarily in that a coextrusion substructure 126a, and a coextrusion substructure 126 b together constitute acoextrusion structure for forming 5-layer melt-laminates 112,122, and tothis end, include three additional sets of shaping inserts (of these,only shaping inserts 103 a,103 b, 104 a,104 b,105 a shown), and in thata partition member 128 divides precursor streams as the streams enterthe coextrusion structure. These inserts, like shaping inserts 102 a,102b and a flow sequencer 150, are beneficially removable from apparatus110. As before, the partition member beneficially is generally centrallydisposed within the coextrusion structure, with respect to thetransverse flow direction.

In FIG. 6, most features of shaping inserts 103 a,103 b,105 a aredepicted in dashed line to emphasize that these inserts, like the othershaping inserts, are disposed within cavities in the body of apparatus110. Previously in connection with FIG. 2, certain of the foregoingfeatures and other aspects have been described. Therefore, like partshave been designated with like numbers, the description of apparatus 110is abbreviated, and reference can be made to the earlier descriptionrelative to apparatus 10.

Feed channels 115,116,117,118,119 conveniently connect between extruders(not shown) and the coextrusion structure of apparatus 110, wherebyprecursor streams A, B, C, D and E respectively enter the coextrusionstructure, as shown. The precursor streams may beneficially beTheologically diverse from each another; however, in any event, streamsB and C are beneficially diverse from stream A, and streams D and E arebeneficially diverse from streams B and C, respectively.

As precursor stream A flows from feed channel 115 into the coextrusionstructure, stream A is divided by a dividing wall 136 a of an elongatedportion 128 a of partition member 128. Referring also to FIG. 7,generally T-shaped, partition member 128 and elongated portion 128 a aremore clearly shown. Thereafter, stream A, now divided, spreads inmanifolds 130 a,130 b in a direction generally transverse to a maindirection of stream A flow indicated by an arrow located in apreconvergence channel 134 a, and enters preconvergence channels 134a,134 b.

With continued reference to FIGS. 6 and 7, as precursor stream B flowsfrom feed channel 116 into the coextrusion structure, stream B isdivided by a dividing wall 136 b of an arm 128 b of a first crossbar 143a of the partition member. Thereafter, stream B, now divided, spreads inmanifolds 140 a,140 b of shaping inserts 102 a,102 b in a directiongenerally transverse to a main direction of stream B flow indicated byarrows located in preconvergence channels 144 a,144 b, and enterspreconvergence channels 144 a,144 b.

Arm 128 b extends between and is disposed adjacent to shaping inserts102 a,102 b. In this way, arm 128 b separates manifolds 140 a,140 b, andseparates preconvergence channels 144 a,144 b, of the shaping inserts,and furthermore provides a side wall 132 b of manifold 140 a andpreconvergence channel 144 a, and a side wall (not shown) of manifold140 b and preconvergence channel 144 b. The side walls of manifolds 140a,140 b converge to provide dividing wall 136 b.

Likewise, as precursor stream C flows from feed channel 117 into thecoextrusion structure, stream C is divided by a dividing wall 136 c ofan opposite arm 128 c of crossbar 143 a of the partition member.Thereafter, stream C, now divided, spreads in manifolds 142 a,142 b ofshaping inserts 103 a,103 b in a direction generally transverse to thedirection of flow indicated by the arrows located in preconvergencechannels 144 a,144 b, and enters preconvergence channels 138 a,138 b.

Arm 128 c extends between and is disposed adjacent to shaping inserts103 a,103 b. In this way, arm 128 c separates manifolds 142 a,142 b, andseparates preconvergence channels 138 a,138 b, of the shaping inserts,and furthermore provides a side wall 132 c of manifold 142 a andpreconvergence channel 138 a, and a side wall (not shown) of manifold142 b and preconvergence channel 138 b. The side walls of manifolds 142a,142 b converge to provide dividing wall 136 c.

Similarly, precursor streams D and E enter the coextrusion structure ofapparatus 110 through feed channels 118,119, which communicate with therespective manifolds of the respective flow-shaping inserts via inletchannels only shaping inserts 104 a,104 b,105 a, inlet channels 127a,127 b, and manifolds 131 a,131 b,135 a are shown in FIG. 6; a shapinginsert, inlet channel and manifold like that shown relative to shapinginsert 104 b are not shown.

Referring again to both FIGS. 6 and 7, as precursor stream D flows fromfeed channel 118 into the coextrusion structure, stream D is divided bya dividing wall 136 d of an arm 128 d of a second crossbar 143 b of thepartition member. Thereafter, stream D, now divided, passes throughinlet channels 127 a,127 b and spreads in manifolds 131 a,131 b ofshaping inserts 104 a,104 b, in a direction generally transverse to thedirection of flow indicated by the arrows located in preconvergencechannels 144 a,144 b, and then enters the respective preconvergencechannels (only part of preconvergence channel 145 a shown).

Arm 128 d extends between and is disposed adjacent to the shapinginserts. As a result, arm 128 d separates inlet channels 127 a,127 b,separates manifolds 131 a,131 b, and separates the preconvergencechannels, of the shaping inserts. Furthermore, arm 128 d provides a sidewall 133 d of inlet channel 127 a, a side wall 132 d of manifold 131 aand preconvergence channel 145 a, a side wall (not shown) of is inletchannel 127 b, and a side wall (not shown) of manifold 131 b and itspreconvergence channel (not shown). The side walls of the inlet channelsconverge to provide dividing wall 136 d. Like the first crossbar,crossbar 143 b is illustrated as being oriented generally perpendicularto elongated portion 128 a of the partition member.

Likewise, precursor stream E flows from feed channel 119 to therespective shaping inserts (only part of insert 105 a shown) of thecoextrusion structure, is divided by a dividing wall 136 e of anopposite arm 128 e of the partition member. Thereafter, stream E, nowdivided, passes through the respective inlet channels, and thereafterspreads in the respective manifolds (only part of manifold 135 a shown)in a direction generally transverse to the direction of flow indicatedby the arrows located in preconvergence channels 144 a,144 b, and entersthe respective preconvergence channels (only part of preconvergencechannel 141 a shown).

As streams A, B and C, now divided, exit from preconvergence channels134 a,144 a,138 a of coextrusion substructure 126 a to merge in a flowconvergence channel 146 a, the shaped streams each advantageously have awidth that corresponds to width w of channel 134 a, and upon merging,form a shaped 3-layer melt-laminate that includes layer interfacescorresponding in width to width w. Downstream thereof, as streams D andE, now divided, exit from preconvergence channels 145 a,141 a ofcoextrusion substructure 126 a to merge in common channel 146 a with theearlier formed 3-layer melt-laminate, shaped streams D,E each also havea width that corresponds to width w of channel 134 a, and upon merging,form a 5-layer melt-laminate 112 (shown in FIG. 5), which includesinterfaces 114 likewise having width w.

Similarly, as streams A, B and C, now divided, exit from preconvergencechannels 134 b,144 b,138 b of coextrusion substructure 126 b to merge ina flow convergence channel 146 b, the shaped streams each advantageouslyhave a width that corresponds to width w′ of channel 134 b, and uponmerging, form a shaped 3-layer melt-laminate laminate that includesinterfaces corresponding in width to width w′. Downstream thereof, asstreams D and E, now divided, exit from the respective preconvergencechannels (not shown) of coextrusion substructure 126 b to merge incommon channel 146 b with the earlier formed 3-layer melt-laminate thatincludes interfaces corresponding in width to width w′, shaped streamsD,E each also have a width that corresponds to width w′ of channel 134b, and upon merging, form a 5-layer melt-laminate 122 (shown in FIG. 5),which includes interfaces 124 likewise having width w′.

As may be understood from FIG. 6, the manifolds of coextrusionsubstructure 126 a beneficially provide the streams exiting from thepreconvergence channels of coextrusion substructure 126 a with width w.Similarly, the manifolds of coextrusion substructure 126 b beneficiallyprovide the streams exiting from the respective preconvergence channelswith width w′. However, width w or w′ could, for instance, alternativelybe provided downstream of a manifold by increasing or decreasing streamwidth in the respective preconvergence channel.

Referring again to FIG. 5, geometrically defined, 5-layer streams112,122 each have a thickness t, which is generally perpendicular torespective interfaces 114,124. As desired, shaped streams 112,122 couldbe wider than thicker (as shown), square, or thicker than wider. Ifdesired, the relative volume or mass of the layers in streams 112,122can be varied by varying the relative volumetric or mass flow rates. Inany event, in accordance with the invention, streams 112,122 aresuitably shaped for subsequent melt-lamination.

Accordingly, in accordance with an advantageous embodiment of thepresent invention, shaped, 5-layer stream 112 including continuous,generally planar interfaces 114 having width w, is formed by mergingshaped streams likewise having width w, and shaped, 5-layer stream 122including continuous, generally planar interfaces 124 having width w′,is formed by merging shaped streams likewise having width w′. Becauseprecursor streams are divided in this embodiment, streams 112,122 haveidentical layer sequencing. If desired, modification of apparatus 110 tobe like the embodiment shown in FIG. 2 in regard to precursor streaminput, would allow streams 112,122 to differ from one another in layersequencing, and in such case, the streams merged to form layered stream112 could be of the same composition as, or differ in composition from,the streams merged to form layered stream 122. Also in such case,differences in extruder output could be used to vary the relative volumeor mass of the shaped, 5-layer streams in the shaped, 10-layer compositesubsequently formed.

Referring both to FIG. 5 and the x-y-z coordinate system depicted and toFIG. 6, at inlets 152 a,152 b of flow sequencer 150, layered streams112,122, suitably shaped for melt-lamination, are conveniently disposedside-by-side along the x-axis. Within the flow sequencer, the shapedstreams each flow generally in the main flow or z-direction, withinterfaces 114,124 generally aligned with the x-axis. In accordance withthe invention, the shaped streams are reoriented in flow sequencer 150as previously described with reference to streams 12,22 to a stackedorientation in which the shaped streams define different planes spacedapart along the y-axis, and melt-laminated to generate a continuous,generally planar interface boundary 164 in a shaped, 10-layer composite162 consisting of shaped layers stacked in the y-direction. Thereafter,shaped layered composite 162 is conveniently passed, without change inwidth or thickness, from the flow sequencer through a connecting channel156 that terminates in an exit slot 157 of apparatus 110. An arrowlocated in connecting channel 156 indicates a main direction of fluidflow from formation of streams 112,122 to exit of shaped layeredcomposite 162 from apparatus 110.

As indicated in FIG. 5, shaped streams 112,122 contribute substantiallyequally to the volume of shaped layered composite 162. However,removability of the shaping inserts advantageously allows relative flowrates to be modified, by for instance, using one or more substituteshaping inserts each having a longer or shorter path length for thepreconvergence channel. Thus, for example, shaping inserts 102 a,103a,104 a,105 a can be exchanged for shaping inserts each having arelatively shorter preconvergence channel path length, and as a result,shaped stream 112 would contribute a relatively greater volume thanshaped stream 122 to the volume or mass of shaped layered composite 162.This advantage likewise may be used to control the relative flow volumesof streams A, B, C, D, and E in either or both of layered streams112,122, whereby, if desired, either or both layered streams can beproduced with layer thickness differences, and even with a layerthickness gradient.

In accordance with the invention and as described relative to theembodiment of FIGS. 1 and 2, shaped layered composite 162 is passed fromapparatus 110 directly or indirectly into an appropriate conventionaldownstream extrusion die, from which a multilayer sheet product exits.Like sheet product 69, this multilayer sheet product has a width greaterthan its thickness, and the interface generated subsequent to streamreorientation is generally parallel to the sheet width.

With reference to FIG. 8, an apparatus 210 is shown that differs fromapparatus 110 of FIG. 6 primarily in that a coextrusion substructure 226a, and a coextrusion substructure 226 b together constitute acoextrusion structure for forming 7-layer streams, and to this end,include two additional sets of shaping inserts, in that a partitionmember 228 includes a third crossbar 243 c, and in that apparatus 210further includes skin layer-forming inserts 208,209. These inserts likethe other inserts and a flow sequencer 250, are advantageously removablyinserted in cavities in the body of apparatus 210. In the Figure, theseinserts and flow sequencer 250 are depicted in solid line for clarity ofview of these features, whereas flow cavities of apparatus 210 areeither omitted or shown in dashed line. As before, partition member 228beneficially is generally centrally disposed within the coextrusionstructure, with respect to the transverse flow direction, so thatcoextrusion substructures 226 a,226 b are generally equal to one anotherin the transverse flow direction.

Previously in connection with apparatus 10 and 110, certain of these andother aspects have been described. Therefore, like parts have beendesignated with like numbers, the description of apparatus 210 isabbreviated, and reference can be made to the prior descriptionsrelative to apparatus 10 and 110.

Feed channels 215,216,217,218,219,220,221 conveniently connect betweenextruders (not shown) and the coextrusion structure of apparatus 210,whereby precursor streams A, B, C, D, E, F and G respectively enter thecoextrusion structure, as shown. The precursor streams may beneficiallybe diverse in rheological properties from each another; however, in anyevent, streams B and C are beneficially diverse from stream A, streams Dand E are beneficially diverse from streams B and C, respectively, andstreams F and G are beneficially diverse from streams D and E,respectively.

Similar to apparatus 110, a 5-layer, geometrically defined melt-laminatehaving a width corresponding to a width w of a channel 244 a is made ina flow convergence channel 246 a from shaped streams exiting theappropriate preconvergence channels of coextrusion substructure 226 aand having a width that corresponds to width w; and a 5-layer,geometrically defined melt-laminate having a width corresponding to awidth w′ of channel 244 b is made in a flow convergence channel (notshown) from shaped streams exiting the appropriate preconvergencechannels of coextrusion substructure 226 b and having a width thatcorresponds to width w′. However, additional layers are added ashereinafter described.

Precursor streams F and G enter the coextrusion structure of apparatus210 through feed channels 220,221, which communicate with the respectivemanifolds of the respective flow-shaping inserts via inlet channels 211.Only flow-shaping inserts 206 a,206 b,207 a, inlet channels 211 a,211 b,and manifolds 225 a,229 a are shown in full or part. An inlet channel(not shown) like inlet channel 211 a, leads to manifold 229 a of insert207 a; inlet channel 211 b leads to a manifold (not shown) like manifold225 a; and an inlet channel (not shown) like inlet channel 211 a, leadsto a manifold (not shown) like manifold 225 a of an insert (not shown).

As precursor stream F flows from feed channel 220 into the coextrusionstructure, stream F is divided by a dividing wall 236 f of an arm 228 fof a third crossbar 243 c of partition member 228. Thereafter, stream F,now divided, passes through inlet channels 211 a,211 b and spreadstransversely in the respective manifolds (only part of manifold 225 ashown) of shaping inserts 206 a,206 b, and enters the respectivepreconvergence channels (only part of preconvergence channel 239 ashown).

Arm 228 f extends between and is disposed adjacent to shaping inserts206 a,206 b. In this way, arm 228 f separates inlet channels 211 a,211b, separates the manifolds, and separates the preconvergence channels,of the shaping inserts. Furthermore, arm 228 f provides a side wall 233f of inlet channel 211 a and a side wall (not shown) of inlet channel211 b. The side walls of the inlet channels converge to provide dividingwall 236 f.

Likewise, precursor stream G is divided by the respective dividingportion of the opposite arm (not shown) of crossbar 243 c of thepartition member. Thereafter, stream G, now divided, passes through therespective inlet channels and spreads transversely in the respectivemanifolds (only part of manifold 229 a shown) of the respective shapinginserts (only part of shaping insert 207 a shown), and enters therespective preconvergence channels (only part of preconvergence channel237 a shown).

As streams F and G, now divided, exit from preconvergence channels 239a,237 a of coextrusion substructure 226 a to merge in common channel 246a with the earlier formed 5-layer melt-laminate, shaped streams F,G eachhave a width that corresponds to width w of preconvergence channel 244a, and upon merging, form a 7-layer melt-laminate that includesinterfaces likewise corresponding in width to width w. As streams F andG, now divided, exit from the corresponding preconvergence channels ofcoextrusion substructure 226 b to merge in the respective common channelwith the earlier formed 5-layer melt-laminate that corresponds in widthto width w′ of preconvergence channel 244 b, shaped streams F,G eachhave a width that corresponds to width w′ of channel 244 b, and uponmerging, form a 7-layer melt-laminate that includes interfaces likewisecorresponding in width to width w′.

Accordingly, in accordance with an advantageous embodiment of thepresent invention, a 7-layer, geometrically defined melt-laminateincluding continuous, generally planar interfaces having width w, isformed by merging shaped streams likewise having width w, and a 7-layer,geometrically defined melt-laminate including continuous, generallyplanar interfaces having width w′, is formed by merging shaped streamslikewise having width w′. Because precursor streams are divided in thisembodiment, the 7-layer melt-laminates have identical layer sequencing.If desired, modification of apparatus 210 to be like the embodimentshown in FIG. 2 in regard to precursor stream input, would allow the7-layer melt-laminates to differ from one another in layer sequencing;and in such case, the streams merged to form one of the 7-layermelt-laminates could be of the same composition as, or differ incomposition from, the streams merged to form the other 7-layer,melt-laminate. Also in such case, difference in extruder output could beused to vary the relative volume or mass of the 7-layer melt-laminatesin the 14-layer shaped layered composite subsequently formed. Ifdesired, the relative volume or mass of the layers in the 7-layermelt-laminates can be varied by varying relative volumetric or mass flowrate.

With continued reference to FIG. 8 and by analogy to FIG. 1, at theinlets of flow sequencer 250 (only inlet 250 a shown), the two generallyrectangularly shaped, 7-layer streams are conveniently disposedside-by-side along the x-axis. Within sequencer 250, the 7-layer streamseach flow generally in the z-direction, with the interfaces generallyparallel to the x-axis, and in accordance with the invention, arereoriented as previously described with reference to streams 12,22, andmelt-laminated to generate a continuous, generally planar interfaceboundary in a shaped, 14-layer composite consisting of shaped layersstacked in the y-direction. Thereafter, the width of the shaped layeredcomposite is increased as in the case of apparatus 10, in adimensional-altering channel 255.

Feed channels 260,261 conveniently connect between extruders (not shown)and manifolds 263,265 of apparatus 210 whereby precursor streams S and Trespectively enter apparatus 210, as shown, to add skin layers to theshaped, 14-layer composite exiting from connecting channel 256. The skinlayers will typically be selected to benefit process and/or productfunctionality. In the respective manifolds, streams S and T spread in adirection generally transverse to a main direction of flow in therespective downstream preconvergence channels 266,267. The maindirection of flow in preconvergence channel 267 is indicated by anarrow. From the manifolds, streams S and T enter respectivepreconvergence channels 266,267. As the fourteen layer composite passesfrom connecting channel 256 and shaped streams S and T pass frompreconvergence channels 266,267 to merge in a combining channel 268, theshaped streams conveniently correspond in width to the composite, andupon merging, form a shaped, 16-layer composite of like width.

Thereafter in accordance with the invention, the resulting compositeexits from apparatus 210 through an exit slot 257, and, as in previousembodiments, is passed directly or indirectly into an appropriateconventional downstream extrusion die, from which a multilayer sheetproduct exits. Like sheet product 69, this sheet product has a widthgreater than its thickness, and the interface generated in the flowsequencer is generally parallel to the sheet width. Arrows located inconnecting channel 256 and combining channel 268 indicate a maindirection of flow from formation of the first layered stream to exit ofthe 16-layer composite from apparatus 210.

With reference to FIG. 9, a shaped melt-laminated stream 312 having agenerally square or rectangular cross-section and including an interface314 having a dimension w, is formed from precursor streams. Also formedare shaped streams 313,323 having dimensions w′, w″, respectively.Conveniently, these dimensions are hereafter referred to as widths. Alsoshown in FIG. 9 is that the shaped, streams each have a dimension t,which conveniently may be referred to as thickness.

With reference to FIG. 10, an apparatus 310 is shown that differs fromapparatus 10 of FIG. 2 in significant respects, including a secondpartition member 328′, a flow sequencer 350 that includes threeflow-sequencing channels 354 a,354 b,354 c, and an interface generatingchannel 360 located downstream of flow sequencer 350 and in whichoriented, sequenced streams are combined. Furthermore, apparatus 310lacks a second flow-shaping insert.

Similar to apparatus 10, a partition member 328 includes an elongatedportion 328 a, and an arm 328 c illustrated as being oriented generallyperpendicular to the elongated portion. Partition member 328′ lacks anarm, but is advantageously disposed generally parallel to the elongatedportion of partition member 328. Beneficially, partition member 328′ andthe elongated portion of partition member 328 are generally spaced apartand disposed with respect to the transverse flow direction, so that aflow-shaping structure 327 of apparatus 310 is partitioned into threegenerally equal portions in the transverse flow direction. In this way,streams leaving preconvergence channel 334 and connecting channels370,370′ of flow shaping structure 327 may be of substantially the samewidth, and the streams entering flow sequencer 350 likewise maysubstantially correspond in width to one another.

Inlets 352 a,352 b,352 c of flow-sequencer 350 receive flow from a flowconvergence channel 346, and from connecting channels 370,370′, throughwhich shaped monolayer streams 313,323 pass. Thus, sequencer 350 orientsand sequences a shaped melt-laminated stream and a pair of shapedmonolayer streams in preparation for forming a shaped layered compositein channel 360.

Previously in connection with FIG. 2, certain of these and other aspectshave been described. Therefore, like parts have been designated withlike numbers, the description of apparatus 310 is abbreviated, andreference can be made to portions of the prior description relative toapparatus 10. Apparatus 310 can be modified to include additionalflow-shaping inserts, and consistent therewith, partition members328,328′ can be appropriately modified by the addition of one or morecrossbars or arms.

Shaping structure 327 forms shaped streams having widths w,w′,w″. Feedchannels 315,316,317,318 conveniently connect between extruders (notshown) and shaping structure 327 and a flow-shaping insert 303.Precursor streams A, B, C and D enter shaping structure 327 and insert303 through these feed channels. Insert 303 beneficially forms a shapedstream having a width corresponding to width w. Typically, the precursorstreams will differ from one another so that diverse streams areadjacent to one another in the product.

Stream A flows from feed channel 315 into manifold 330 a of shapingstructure 327 and spreads in the manifold in a direction generallytransverse to a main direction of stream A flow indicated by an arrowlocated in connecting channel 370, and thereafter enters preconvergencechannel 334. Similarly, streams B and C flow from feed channels 316,317into manifolds 330 b,330 c of shaping structure 327, are spread in themanifolds in a direction generally transverse to a direction of flowindicated by the arrow located in connecting channel 370, and enterconnecting channels 370,370′.

Likewise, stream D flows from feed channel 318 into flow-shaping insert303. Specifically, stream D enters manifold 342 and spreads in themanifold in a direction generally transverse to the main direction ofstream D flow, and thereafter enters preconvergence channel 338 of theinsert. Arm 328 c of partition member 328 is beneficially disposedadjacent an interior side of the flow-shaping insert, and in this wayprovides a side wall 332 c of the manifold and preconvergence channel ofthe insert.

A coextrusion structure 326 provides for shaping and convergence ofstreams A and D, and includes manifold 330 a and preconvergence channel334 of shaping structure 327, the flow-shaping channel provided by theflow-shaping insert, and flow convergence channel 346. As streams A andD exit from preconvergence channels 334,338 to merge in flow convergencechannel 346, the shaped streams each advantageously have a width thatcorresponds to width w of channel 334, and upon merging, form shaped,melt-laminated stream 312, which includes layer interface 314 likewisehaving width w. Conveniently, a relatively greater extruder output isused for stream A than for stream D, as a result of which the flowvolumes of streams A,D are substantially different as these streams formmelt-laminate 312, which is thus characterized by, as indicated by FIG.9, relatively greater volume of the A layer than the D layer.

Referring also to FIG. 9 and to the x-y-z coordinate system depicted, atinlets 352 a,352 b,352 c of flow sequencer 350, streams 312,313,323,suitably shaped for melt-lamination, are conveniently disposedside-by-side along the x-axis. Within the flow sequencer, the shapedstreams each flow generally in the main flow or z-direction, and thex-axis is generally in alignment with widths w,w′,w″. In accordance withthe invention, the shaped streams are oriented and sequenced withinsequencer 350 so that they are in a selected, stacked orientation alongthe y-axis prior to melt-lamination. Conveniently, only streams 312,323are reoriented, the reorientation being along both the x-axis andy-axis. As the streams pass from flow sequencer 350 into channel 360,the shaped streams are melt-laminated within channel 360 along majorsurfaces thereof defined by an x-z plane, to generate continuous,generally planar interface boundaries 364 in a shaped layered composite362 consisting of shaped layers stacked in the y-direction.

As indicated in FIG. 9, shaped layered stream 312 contributes the mostto the volume of shaped layered composite 362, stream 313 contributes asmaller proportion to the volume, and stream 323 contributes thesmallest proportion to the volume, thereby producing a layer thicknessgradient. As before, the relative volume or mass can be controlled byrelative volumetric or mass throughput of the flow streams.Conveniently, relatively greater extruder output is used for streams A,Dthan for streams B,C, and relatively greater extruder output is used forstream B than for stream C.

Flow sequencer 350 beneficially is an assembly of a plurality of plates375,376,377,378 with surface channels (not shown) that combine to formthe flow-sequencing channels. A skilled artisan by comparison to thedetails of FIG. 4, will readily understand suitable surface channelshapes, locations and orientations for constructing the flow-sequencingchannels of sequencer 350.

Thereafter in accordance with the invention, shaped layered composite362 exits from apparatus 310 through an exit slot 357, and, as inprevious embodiments, is passed directly or indirectly into anappropriate conventional downstream extrusion die, from which exits amultilayer sheet product 369 of increased width, illustrated in FIG. 9.Like sheet product 69, sheet product 369 has a width W greater than athickness T, and the interfaces generated after stream reorientation,are generally parallel to the sheet width, and to earlier-formedinterface 314. Arrows located in channels 360 and 370 indicate a maindirection of fluid flow until exit of shaped layered composite 362 fromapparatus 310.

As previously indicated, a shaped layered composite may be convergedwith other streams prior to entry into the downstream extrusion die. Insuch case, flow sequencer removability may be of special benefit. Forexample, instead of converging composite 362 with a like compositehaving layer sequence C/B/D/A, a coherent mass having layer sequenceC/B/D/A/D/A/B/C could be produced by removing flow sequencer 350,rotating the flow sequencer 180 degrees and reinserting the flowsequencer.

With reference to FIG. 11, an apparatus 410 is shown that differs fromapparatus 310 of FIG. 10 in significant respects, including a manifold431, a connecting channel 471, and an inlet 452 c offset respectivelyfrom manifolds 430 a,430 b, from channels 446,470, and from inlets 452a,452 b. Thus, inlets 452 a,452 b,452 c of flow sequencer 450 are nolonger side-by-side, but, for purposes of this invention, are generallyside-by-side. Furthermore, a different flow sequencing arrangement ofchannels 454 a,454 b,454 c is shown. Also, apparatus 410 lacks a secondpartition member, and thus a flow-shaping structure 427 of apparatus 410is beneficially partitioned by a removable partition plate into two, notthree, generally equal portions in the transverse flow direction.

However, other aspects are similar including melt-laminating ininterface generating channel 460, after stream reorientation in flowsequencer 450. Previously, certain of these and other aspects have beendescribed; therefore, like parts have been designated with like numbers,and reference can be made to the pertinent, prior descriptions relativeto apparatus 10 and 310.

If desired, the embodiment of FIG. 11 could be further modified so thatinlet 452 a is offset from inlet 452 b in a direction opposite to inlet452 c. In such case, for purposes of this invention, flow sequencerinlets 452 a,452 b,452 c would be generally side-by-side to one another,even though inlets 452 a,452 b,452 c were offset from one another and inthree parallel planes. Thus, “generally side-by-side” is meant forpurposes of this invention, to include an arrangement of flow sequencerinlets that if not coplanar, would be side-by-side if the respectiveoffset planes were aligned.

Having described the invention in detail and by reference to preferredembodiments thereof, it will be apparent that other modifications andvariations are possible without departing from the scope of theinvention defined in the appended claims.

1. A method for producing a shaped layered composite comprising aninterface defined by melt-lamination of overlapping flow streams,wherein said interface lies generally in an x-z plane of an x-y-zcoordinate system in which the x-axis defines a transverse dimension ofsaid interface and the y-axis extends generally perpendicularly throughsaid interface, said method comprising with a first shaped flow streamand a second shaped flow stream each having a main flow directiongenerally in the z-direction, and said first shaped flow stream and saidsecond shaped flow stream being suitably-shaped for melt-lamination,changing the relative orientation of said first shaped flow stream tosaid second shaped flow stream from a generally side-by-side orientationalong said x-axis to a generally stacked orientation in which said firstshaped flow stream defines a first plane and said second shaped flowstream defines a second plane along said y-axis, thereafter forming saidinterface of said shaped layered composite by melt-laminating said firstshaped flow stream and said second shaped flow stream, wherein saidlayered composite is formed independent of division of a layeredprecursor stream, and thereafter dimensionally increasing said interfacealong said x-axis to form a multilayered composite product of greaterwidth than thickness, wherein said interface is generally parallel tosaid width.
 2. The method of claim 1, wherein said first shaped flowstream and said second shaped flow stream are co-planar to one anotherin said generally side-by-side orientation.
 3. The method of claim 1,wherein said first shaped flow stream and said second shaped flow streamare in different planes from one another in said generally side-by-sideorientation.
 4. The method of claim 1, wherein said first shaped flowstream and second shaped flow stream are layered streams, and said firstshaped flow stream differs from said second shaped flow stream in layersequencing, but the streams merged to form said first shaped flow streamare of the same composition as the streams merged to form said secondshaped flow stream.
 5. The method of claim 1, wherein said first shapedflow stream and said second shaped flow stream are layered streams, andsaid first shaped flow stream differs from said second shaped flowstream in layer sequencing, and at least one of the streams merged toform said first shaped flow stream differs in composition from each ofthe streams merged to form said second shaped flow stream.
 6. The methodof claim 1, wherein said first shaped flow stream and said second shapedflow stream are layered streams, and said first shaped flow stream andsaid second shaped flow stream have identical layer sequencing.
 7. Themethod of claim 1, wherein said first shaped stream flow stream or saidsecond shaped flow stream is a layered stream and during the step offorming said first shaped stream or said second shaped stream, there isa substantial difference in the volumetric or mass flow rates of atleast two of the streams being merged.
 8. The method of claim 1, whereinduring the step of forming said shaped layered composite, there is asubstantial difference in the volumetric or mass flow rate of said firstshaped flow stream compared to said second shaped flow stream.
 9. Themethod of claim 1, wherein said first shaped flow stream is a layeredstream comprising at least one interface having a width w, and at leasttwo of the streams merged to form first shaped flow stream have saidwidth w, and wherein said second shaped flow stream is a layered streamcomprising at least one interface having a width w′, and at least two ofthe streams merged to form said second shaped flow stream have saidwidth w′. 10-20. (cancelled)